Remote capacitive interface

ABSTRACT

Computing devices, input devices, keyboard assemblies, and related systems include a set of conductive traces or leads configured to transfer a capacitive load from an appendage of a user or another capacitive load source from a remote location, such as on a keycap of the keyboard, to a conductive portion or electrode on the keyboard that is positioned near a touch-sensitive interface of a computing device. The capacitive load is thereby transferable through the conductive traces or leads to the touch-sensitive interface without having to directly apply the load, such as by touching a finger to the interface. This can reduce or eliminate the need for on-screen controls or keyboard interface elements in a touch screen device without having to use a more expensive and energy-draining wired or wireless connection between the computing device and a keyboard case or accessory for the computing device.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/444,938, filed 18 Jun. 2019, and entitled “REMOTE CAPACITIVEINTERFACE,” which claims priority to U.S. Provisional Patent ApplicationNo. 62/727,391, filed 5 Sep. 2018, and entitled “REMOTE CAPACITIVEINTERFACE,” the disclosures of which are hereby incorporated byreference in their entireties.

FIELD

The described embodiments relate generally to interfaces for electronicdevices. In some specific examples, the present embodiments relate tokeyboards for touch screen devices.

BACKGROUND

Many electronic devices have keyboards and related devices to receiveinput and interaction from users. These electronic devices includecomputers, such as personal computers, tablet computers, andsmartphones, and other “smart” devices, such as media players, video andaudio equipment, vehicle consoles, home automation controllers, andrelated devices. Keyboards and other interface devices are designed withbuttons or keys that are pressed by users to generate input signals fora processor or controller. These devices are often designed to provide acontrolled amount of resistance to the user's fingertips in order togive tactile feedback as the user presses a button or key. The feel,sound, cost, and size of each button or key are tightly controlled toefficiently provide a desired user experience. Although some keyboardsare “virtual,” such as software keyboards displayed on a touchscreendevice, it can be beneficial to provide key travel, or movement of thekeys, to help the user more easily feel, see, and hear when and where akey is pressed and to provide an overall more satisfying interactionwith the device.

Providing this type of key or button can come with costs. Touchscreendevices that do not have a built-in mechanical keyboard can be connectedto a peripheral keyboard interface device, but that peripheral devicemust have an independent power source or must have a wired connection tothe touchscreen device that can drain the power source of thetouchscreen device or can require special electrical connectors to theperipheral device. Thus, there are many challenges and areas forimprovements in interface devices.

SUMMARY

One aspect of the disclosure relates to a computing device and keyboardassembly. The computing device can have an external surface and atouch-sensitive interface. The keyboard can be removably coupled to thecomputing device, with the keyboard having a contact section and aninput section. The contact section can contact the external surface ofthe computing device, wherein a set of conductive traces can extendthrough the contact section and the input section. Each conductive traceof the set of conductive traces can comprise a first conductive portionlocated in the contact section and a second conductive portion locatedin the input section. Application of a capacitive load to one of thesecond conductive portions of the set of conductive traces can bedetectable by the touch-sensitive interface via the first conductiveportion.

The computing device can be a tablet computer, and the keyboard canfurther comprise a set of switches arranged in a keyboard layout, witheach switch of the set of switches being connected to a respectivesecond conductive portion of the set of conductive traces. Thecapacitive load can be applied by an appendage of a user, and the set ofswitches can selectively enable or disable electrical communicationbetween the capacitive load and the touch-sensitive interface via therespective second conductive portion.

The first conductive portions can contact the touch-sensitive interface.The touch-sensitive interface can comprise a display screen portion,wherein the first conductive portions of the set of conductive tracescan overlap the display screen portion. The touch-sensitive interfacecan be positioned on the computing device external to a display screenof the computing device. The external surface can face away from thedisplay screen of the computing device. The first conductive portions ofthe set of conductive traces can be distributed across an edge portionof the computing device. The computing device can be configured todetect a presence of the contact section of the keyboard against theexternal surface.

Another aspect of the disclosure relates to a keyboard, comprising ahousing having a first section and a second section, with the firstsection having an external surface configured to face an electronicdevice and with the second section being configured to extend away fromthe electronic device. The keyboard can also include a set of conductiveleads positioned in the housing, with each conductive lead of the set ofconductive leads comprising a first conductive portion positioned at theexternal surface of the first section and configured to contact theelectronic device and a second conductive portion positioned in thesecond section. The second conductive portions can be arranged in akeyboard layout, and each of the second conductive portions of the setof conductive leads can be configured to transfer capacitive loads tothe respective first conductive portions.

The keyboard can further include a set of switches, wherein each switchof the set of switches can be connected to a separate second conductiveportion of the set of conductive leads. The keyboard can also include aset of keys, wherein each key of the set of keys comprises a conductiveinput surface. The conductive input surfaces can be electricallyconnectable to a respective second conductive portion of the set ofconductive leads via a respective switch of the set of switches. Acapacitive load source can also be included, wherein each switch of theset of switches comprises a releasable connection to the capacitive loadsource. The capacitive load source can be located in the first sectionof the housing. A hinge can be positioned between the first and secondsections of the housing.

In yet another aspect of the disclosure, a capacitive keyboard isprovided that can include a set of conductive traces each having a firstend and a second end and a set of keys each comprising a keycap and aswitch, wherein each switch is respectively electrically connected toone of the second ends of the set of conductive traces. The switches canbe respectively actuatable to transfer a capacitive load from arespective key of the set of keys to a respective first end of the setof conductive traces.

In some embodiments, each of the keycaps of the set of keys can comprisea conductive surface, wherein the capacitive load can be transferablefrom the conductive surface to the respective conductive trace. Thekeyboard can also have a housing, with the set of keys being positionedon the housing, and wherein each switch is electrically connected to acapacitive load source in the housing. The capacitive load source can bean electrical ground or can be a virtual ground when connected to aconductive trace of the set of conductive traces. The first ends of theset of conductive traces can be arranged in a staggered pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings and figures illustrate a number of exemplaryembodiments and are part of the specification. Together with the presentdescription, these drawings demonstrate and explain various principlesof this disclosure. A further understanding of the nature and advantagesof the present invention can be realized by reference to the followingdrawings. In the appended figures, similar components or features canhave the same reference label.

FIG. 1 shows a block diagram of a computing device and input deviceassembly according to an embodiment of the present disclosure.

FIG. 2 shows a perspective view of a computing device and an inputdevice according to an embodiment of the present disclosure.

FIG. 3 shows an exploded side view of the assembly of FIG. 2.

FIG. 4 shows a partial breakaway and exploded front view of the assemblyof FIG. 2.

FIG. 5 shows a diagrammatic side section view of the input device ofFIG. 2 as taken through section lines 5-5 in FIG. 4.

FIG. 6 shows an exploded perspective view of an embodiment of acomputing device and an input device according to another embodiment ofthe present disclosure.

FIG. 7 shows a partial breakaway front view of an embodiment of an inputdevice of the present disclosure.

FIG. 8 shoes a diagrammatic side section view of the input device ofFIG. 7 as taken through section lines 8-8 in FIG. 7.

While the embodiments described herein are susceptible to variousmodifications and alternative forms, specific embodiments have beenshown by way of example in the drawings and will be described in detailherein. However, the exemplary embodiments described herein are notintended to be limited to the particular forms disclosed. Rather, theinstant disclosure covers all modifications, equivalents, andalternatives falling within the scope of the appended claims.

DETAILED DESCRIPTION

The present description provides examples, and is not limiting of thescope, applicability, or configuration set forth in the claims. Thus, itwill be understood that changes can be made in the function andarrangement of elements discussed without departing from the spirit andscope of the disclosure, and various embodiments can omit, substitute,or add other procedures or components as appropriate. For instance,methods described can be performed in an order different from thatdescribed, and various steps can be added, omitted, or combined. Also,features described with respect to some embodiments can be combined inother embodiments.

Computing devices, including touch screen devices such as, for example,tablet computers and smartphones, are widely used and are valuable toolsfor communication, viewing content, working, recreation, and so forth.Input can be provided to the computing device using a touch-sensitiveinterface. A touch-sensitive interface, as used herein, refers to adisplay screen that includes touch- or near-touch-sensitive sensors inthe device, wherein when a user contacts the surface of the device witha capacitive load source, the device can detect the presence of thecapacitive load source. For example, a touch-sensitive interface can bea capacitive touch-sensitive interface using a surface capacitive touchscreen, a projected capacitive touch screen, a surface acoustic wave(SAW) touch screen, related technologies, and combinations thereof. Acapacitive load source, as used herein, refers to a device or personthat can be detected by use of the touch-sensitive interface. Forexample, a capacitive load source can be a user's appendage (e.g.,finger), a charged stylus, another electrically absorptive instrument, aconnection to electrical ground or a virtual ground, a capacitivegrounding element, related devices, and combinations thereof. In someembodiments, a mutual capacitance touch screen can be used, wherein thecapacitive load source can be detected by the touch screen due toelectrical absorption of the instrument to locally reduce the charge inan electrically charged layer of the touch screen.

Although the touch-sensitive interface of a touch screen device isversatile and can simulate a keyboard (e.g., by creating a “virtual”software-based keyboard in the display screen for the user to type on),the flat, hard surface of the touch screen and the low angle at whichthe touch-sensitive interface is oriented can make typing on the deviceless desirable than on a peripheral keyboard device. The keyboard andthe typist's hands can also take up and cover a significant amount ofusable space on the touch screen.

As compared to a virtual on-screen keyboard, a peripheral keyboardaccessory can have mechanical switches for the keys that provide adifferent tactile feel and audible feedback and can be oriented at amore comfortable angle since it is movable relative to the screen. Insome cases, the mechanical switches (e.g., collapsible domes orspring-loaded switches) can have mechanical supports such as butterflyor scissor switch guides. The peripheral keyboard also takes up less, ifany, display screen space. However, most peripheral keyboards require awired or wireless connection to the touch screen device. A wiredconnection can complicate the design of the touch screen device sincepower and space in the device is needed for components that produce orread the signals coming from the peripheral keyboard. Those componentscan also drain the power source of the touch screen device while active.A wireless connection to a peripheral device requires an independentpower source in the peripheral device and a wireless interface on thetouch screen device, both of which add to the cost and energyconsumption of the pair.

Aspects of the present disclosure relate to a peripheral input device(e.g., a keyboard, controller, or related accessory) using remotecapacitive load transmission to enable the user to interact with atouch-sensitive interface (e.g., a touch screen interface) of the touchscreen device without having to move a capacitive load source intophysical contact with the touch-sensitive interface. In a non-limitingexample, a user can type on a keyboard that is attached to the touchscreen device, and the touch screen device can effectively receive inputvia electrodes in the keyboard as if a user's fingers were touching thetouch-sensitive interface. In another example, the user can press a keyon the keyboard that enables an electrical connection between acapacitive load (e.g., a connection to ground or a source with lowimpedance to ground) and electrodes at the touch-sensitive interface tosimulate the user's touch without actually transferring the user'scapacitive load to the interface. In either case, the user can type at acomfortable angle and with the tactility and audible feedback thatcannot be provided by a flat, hard touch screen. Additionally, thekeyboard does not need to draw any power from the device or have a powersource of its own.

Electrical loads or signals can be transferred through passive (i.e.,non-electrically charged) conductive paths in the input device from thecapacitive load source to the touch-sensitive interface of the touchscreen device in order to simulate interaction between the capacitiveload source and the touch-sensitive interface. In this manner, the inputdevice does not need its own power source since it acts as a passiveelectrical conduit between the capacitive load source and thetouch-sensitive interface. The touch of the capacitive load sourceagainst a key on the input device adds a capacitive load to one end ofthe conduit that is transferred to the other end of the conduit that ispositioned adjacent the touch-sensitive interface. The touch-sensitiveinterface can detect the change in capacitive load and react as if thecapacitive load source had contacted the touch-sensitive interfacedirectly.

The touch screen device is also not required to provide additional powerand circuitry to make an electrical connection to the input device(e.g., a wired connection). The same touch-sensitive interface of thetouch screen device can be used for receiving input from the capacitiveload source via the input device and from normal user interaction with acapacitive load source directly against the touch-sensitive interface.

In some embodiments, the input device is attached to the touch screendevice in a manner partially covering the display screen. In otherembodiments, the input device contacts the touch screen device on atouch-sensitive interface of the touch screen device without coveringthe display screen. For example, a bezel or side portion of the front ofthe touch screen device can be configured with a touch-sensitiveinterface portion that can be connected to the input device. The back ofthe device can also have the touch-sensitive interface. Thus, in variousconfigurations, the input device can access touch-sensitive interfaceson the device that are separate from the display screen.

In some embodiments, the input device can be removably attachable to thetouch screen device. In one case, the input device is held to the touchscreen device by magnets, clips, straps, or other housing or caseportions attached to the keyboard that help orient the input devicerelative to the touch screen device and help to keep the input device inproper alignment with the touch-sensitive interface. The touch screendevice can be configured with sensors or switches that detect thepresence of the input device. In this manner, the touch screen devicecan include software such as a user interface that reacts to thepresence of the input device. For example, when keyboard input is neededon the touch screen device, the touch screen device can determinewhether or not an on-screen keyboard is displayed based or whether ornot the input device is present. In some cases, such as when the inputdevice partially covers the display screen, the user interface can bemodified based on the covered screen space to avoid having informationobscured from the user.

The input device can be part of a cover or case for the computingdevice, wherein the input device has portions or sections that arehinged or foldable relative to each other and can be movable between aninput position where the keyboard portion and display screen of thedevice are accessible and visible for typing and a position wherein atleast the display screen is covered and the input device is stored.

Additional detail and embodiments are shown in the figures and describedbelow. FIG. 1 is a block diagram illustrating the relationship of asystem 100 of a computing device 102 and an input device 104. Thecomputing device 102 can have an external surface 106 and atouch-sensitive interface 108. The input device 104 can be removablycoupled to the computing device 102, wherein a contact section 110 ofthe input device 104 contacts or is in close proximity to (e.g., a fewmillimeters or less removed from) the external surface 106 of thecomputing device 102. The input device 104 can include a set ofconductive traces 112. In one embodiment, 26 or more conductive tracesare included. Alternatively, 60 or more conductive traces can beincluded. For simplicity, only one of the conductive traces 112 is shownin FIG. 1. The conductive trace 112 can have a first conductive portion114 located in the contact section 110 and a second conductive portion116 located in an input section 118 of the input device 104. In someembodiments, the second conductive portion 116 can be connected to aswitch 120 that selectively provides a connection between the secondconductive portion 116 and a capacitive load source 122.

The system 100 can be referred to as an assembly of the computing device102 and the input device 104. The input device 104 can be removablyattached to the computing device 102 and, when attached, can be heldagainst or latched to the computing device 102. The computing device 102can be any type of electronic device configured to receive input via atouch-sensitive (e.g., capacitive-load-sensitive) interface. Forexample, without limitation, the computing device 102 can include, butis not limited to, personal computers (including, for example, computer“towers,” “all-in-one” computers, computer workstations, notebookcomputers, laptop computers, and related devices), graphics tablets,smart watches, other wearable devices, vehicles and related componentsand accessories, servers, screens, displays, and monitors, photographyand videography equipment and related accessories, printers, scanners,media player devices, point-of-sale equipment, home automationequipment, and any other electronic device that uses, sends, or receiveshuman input or that can use a keyboard or a related device for input.Thus, the example tablet computer shown in the figures should be viewedas merely exemplary of the many different types of computing devicesthat can be implemented with the input devices disclosed herein. Thecomputing device 102 can comprise a processor 101 (or similarcontroller) in electrical communication with the touch-sensitiveinterface 108 and configured to control the computing device 102 inresponse to receiving signals from the touch-sensitive interface.

The input device 104 can be a peripheral keyboard, accessory, case, orcover for the computing device 102. The outer dimensions of the inputdevice 104 can be similar or equal to the outer dimensions of thecomputing device 102 in order to facilitate portability of the system100 of devices 102, 104. The input device 104 can be detachable from thecomputing device 102 by applying a force to the input device 104 tosever the forces holding together magnetically attracted elements in thecomputing device 102 and the input device 104. The input device 104 cancomprise a keyboard such as a QWERTY (or similar layout) keyboard. Theinput device 104 can be embodied as a type of keyboard, such as, forexample, a keyboard having keys arranged in straight rows, straightcolumns, straight rows and columns combined, or in another distributedor staggered layout. In certain embodiments, the keyboard can have agreater number of keys, or a fewer number of keys than illustrated inthe figures. See, e.g., FIGS. 2-4 and 6-7. The keys can be arranged inmultiple different layouts. For example, the keys can be arranged in anANSI (American National Standards Institute) layout, AZERTY layout, ISO(International Organization for Standardization) layout, Dvorak layout,Colemak layout, or other related configuration. The keys can have acompact layout (such as the compact layout of FIG. 2), a tenkeylesslayout, 60% layout, 65% layout, 75% layout, full-size layout,numpad-only layout, or other configuration as needed to meet desiredspace, cost, and ergonomic considerations. As illustrated herein, theone or more keys may be of different sizes and may be positioned atdifferent locations along the surface of the keyboard.

The input device 104 can include a chassis or housing 124 in which theconductive traces 112 are housed or embedded. In some arrangements, thehousing 124 can include one or more bendable sections, foldablesections, or hinged sections connected to each other. For example, thecontact section 110 and the input section 118 can be connected to eachother by a hinge 130. The housing 124 can have an external surface 126comprising or near the first conductive portions 114 that is configuredto face or contact the external surface 106 of the computing device 102.The input device 104 can also include portions (not shown) that areconfigurable to form a stand or support for the computing device 102.For example, the input device 104 can be configurable to keep thecomputing device 102 held in an upright position (e.g., as shown in FIG.2) or at another orientation relative to the input device 104 orrelative to a horizontal support surface beneath the assembly.

The external surface 106 of the computing device 102 can be a surface ofthe device 102 that is adjacent to or external to the touch-sensitiveinterface 108. The external surface 106 can therefore be a surfacethrough which touch input (e.g., a capacitive load) can be detected bythe touch-sensitive interface 108. In some embodiments, the externalsurface 106 comprises a glass (or other ceramic), polymer, or metalmaterial that, when contacted by a capacitive load source (e.g., aperson's finger) can transfer the load to the touch-sensitive interface108. The external surface 106 can therefore be the outer surface of adisplay screen of a touch screen interface of the computing device 102or another front, side, or back surface of the computing device 102through which a capacitive load can be detected by the touch-sensitiveinterface 108, or combinations thereof. In some embodiments, theexternal surface 106 includes a portion of one of the sides of thecomputing device 102, such as a section of a side of a bezel portion ofthe front of the computing device 102 or a portion of the rear surfaceof the computing device 102. The capacitive load source can be detectedby the touch-sensitive interface 108 resulting from contact between aconductive pad or lead positioned in the input device 104 and theexternal surface 106. In some cases, the capacitive load source can bedetected by the touch-sensitive interface 108 at a close distance ofseparation from the external surface 106, such as through thinintermediate layers with appropriate permittivity to allow thecapacitive load to be sensed through them (whether the intermediatelayers are on the input device 104 or the external surface 106).

The touch-sensitive interface 108 can be any touch-sensitive electroniccomponent configured to receive a capacitive load from a capacitive loadsource such as a finger or other source having low impedance to ground.For example, the touch-sensitive interface 108 can comprise a mutualcapacitive touch sensor array used in touchscreen tablets, phones, andrelated devices or other touch-sensitive interfaces described elsewhereherein. The touch-sensitive interface 108 can include portions at ornear a display screen of the computing device 102 and can extend intoportions of the computing device 102 external to or positioned on anopposite side of the device 102 from the display screen.

The contact section 110 of the input device 104 can include the firstconductive portions 114 of the conductive traces 112. The contactsection 110 can be configured to include the external surface 126 of thehousing 124. Thus, the contact section 110 can be arranged in contactwith the external surface 106 of the computing device 102. The contactsection 110 can also comprise attachment devices 128, such as magnets orfasteners, that keep the contact section 110 removably secured to thecomputing device 102. The attachment devices 128 can be configured tokeep the first conductive portions 114 in a certain position on theexternal surface 106 of the computing device 102.

The conductive traces 112 can comprise a conductive material (e.g.,copper, silver, aluminum, conductive polymer, ceramic material, otherconductive material, or combinations thereof) running through thehousing 124. The conductive traces 112 can extend through the inputdevice 104, including across a boundary, fold, or hinge 130 between thecontact section 110 and the input section 118. In a keyboardconfiguration of the input device 104, each key can be electricallyconnected to a different, unique conductive trace 112. Thus, theconductive traces 112 can be insulated from each other so thatelectrical signals borne by one conductive trace 112 are onlytransferred to the touch-sensitive interface 108 by that conductivetrace 112. As explained in greater detail below, each of the conductivetraces 112 can have ends (e.g., the first and second conductive portions114, 116) located at unique positions on the contact section 110 and onthe input section 118. The conductive traces 112 can also be insulatedalong their lengths between the first and second conductive portions114, 116 to avoid interference with signal transmission or shorting toother conductive traces, such as by being embedded between insulatedlayers of material in the housing 124.

A first conductive portion 114 of each conductive trace 112 ispositioned in the contact section 110 of the device. In someembodiments, the first conductive portions 114 of the traces 112 cancomprise conductive electrodes that are exposed on the surface of thecontact section 110 and configured to be external to the touch-sensitiveinterface 108 and the external surface 106 of the computing device 102.In some embodiments, the first conductive portions 114 are within thehousing 124 and are electrically connected to conductive material thatlinks the first conductive portions 114 to the outer surface 126thereof.

The sensing of a capacitive load at the first conductive portion 114 bythe touch-sensitive interface 108 is represented by line 132 in FIG. 1.Line 132 is represented as a dashed line to indicate that there is nowired, conductor-to-conductor connection between the input device 104and the computing device 102 in order to make the sensing of thecapacitive load possible. There is also no powered, two-way wirelesscommunication between the input device 104 and the computing device 102(e.g., via WI-FI®, BLUETOOTH®, RFID, ZIBGEE®, cellular communication, oranother similar wireless communication specification). Instead, thefirst conductive portion 114 passively reproduces a capacitive loadapplied to the conductive trace 112, and the computing device 102 sensesthat load as if the load were applied directly to the external surface106 without the conductive trace 112 being present.

The second conductive portion 116 can be positioned in the input section118 of the input device 104. The second conductive portions 116 can bearranged in a keyboard layout in the input section 118. Each of thesecond conductive portions 116 can be electrically connected to a uniqueswitch 120. Application of a capacitive load to the second conductiveportion 116 causes the conductive trace 112 to reproduce the capacitiveload at the respective first conductive portion 114.

The input section 118 can comprise a keys, switches, or buttons that canbe used to interface with the computing device 102. The input section118 can be formed in a stiffened portion of the housing 124 so that thekeyboard it supports remains flat and supportive of the keys andswitches. In some embodiments, the input section 118 has outerdimensions substantially similar to the outer dimensions of thefront-facing surface of the computing device 102 so as to completelycover the front-facing surface when the input device 104 is folded orstored against the computing device 102.

The switch 120 connected to the second conductive portion 116 can be anelectrical switch such as a momentary contact switch that makes orbreaks connection as long as pressure is applied to the switch (e.g.,when a button or key connected to the switch 120 is pressed). Oncepressure is removed, the switch 120 can return to its original,un-pressed position. This functionality can be provided to the switch120 using a resilient collapsible dome, a spring, a compliant mechanism,or related device that moves a contactor in the switch 120 between afirst position enabling electrical conduction through or past the switchand a second position disabling such electrical conduction. In someembodiments, the switch 120 provides a momentary contact for aconductive path starting in a keycap/button (or on the surface of thekeycap/button) and extending to the second conductive portion 116,thereby also providing a conductive path to the first conductive portion114. Accordingly, if a capacitive load source 122 (e.g., a user'sfinger) presses down on the keycap, the first conductive portion 114 canabsorb energy from the touch-sensitive interface 108 (or otherwise applythe capacitive load to it) when the switch 120 enables the conductivepath to the first conductive portion 114.

In another embodiment, the switch 120 can provide an electricalconnection to a capacitive load source 122 that is not a finger or otherinstrument applied to the keycap. For example, another capacitive loadsource can be selectively connected to the second conductive portion 116by the switch 120. The other capacitive load source 122 can bepositioned within the input device 104, such as a relatively largeconductive object (relative to the first conductive portion 114) that,when connected to the conductive trace 112, makes the conductive tracehave a low impedance to ground, thereby simulating the capacitive loadof a finger or other charged instrument against the touch-sensitiveinterface 108.

Detail about a related embodiment is shown in FIGS. 2-4. In thesefigures, a system 200 includes a computing device 202 and input device204 shown from various orientations and in various degrees ofseparation. FIG. 2 is a perspective view, FIG. 3 is an exploded sideview with the computing device 202 in a different orientation relativeto FIG. 2, and FIG. 4 is a partial breakaway and exploded front viewwith the input device 204 in a different configuration relative to FIGS.2 and 3. In FIG. 4, a top surface layer and keycaps 214 of the inputdevice 204 are partially removed to show conductive pads (e.g., 228,232) and to illustrate conductive traces 226 through the input device204.

In these embodiments, the computing device 202 is a tablet computerhaving a housing 206 and a front surface 208 through which a user caninteract with the device 202 using a touch-sensitive interface which, inthis case, is a touch screen 210. The input device 204 is shown with akeyboard 212 including a set of keys 214 arranged in a keyboard layout.The keys 214 can have different shapes and sizes, as shown. Each key 214can be configured with its own switch (e.g., switch 120; see also FIG. 5and related description below). The keys 214 can each have a label orglyph (not shown) on their top surfaces.

The input device 204 can have an input section 216 and a contact section218 linked to each other by a bend, fold, or hinge 220. The inputsection 216 and contact section 218 can be movable relative to eachother at the hinge 220. This can enable the computing device 202 to beoriented at different angles X, X′ relative to the input device 204, asillustrated by FIGS. 2 and 3, without the computing device 202 beingdisconnected from the input device 204.

The contact section 218 can be magnetically attracted to the computingdevice 202, such as by being attracted to the front surface 208 thereof.In other embodiments, the contact section 218 can be attached to thecomputing device 202 in another way, such as by being strapped, clipped,or latched onto the computing device 202, being integrated into a casefor the computing device 202, or related techniques. The computingdevice 202 can be configured with sensors (e.g., Hall-effect sensorsdetecting a magnet in the input device 204) that detect the presence ofthe input device 204. Detecting the presence of the input device 204 cancause the computing device 202 to change its software settings (e.g., bythe processor 101 executing software instructions stored in memory onthe computing device).

The input section 216 can have a top surface 222 from which the keys 214extend and that is configured to face upward. The contact section 218can have an external surface 224 (see FIG. 3) at which contactors (e.g.,first conductive portions 114) can be located. The top surface 222 cancomprise a flexible surface layer (not shown) covering the keys 214 orexternal surface 224 and providing a barrier against debris and moisturepenetrating the keys 214, external surface 224, or other space withinthe input device 204. In some embodiments, the flexible surface layercan comprise a conductive flexible material such as a conductive polymerthrough which a capacitive load can be transferred to the keys 214 upontouching the flexible surface layer. The flexible surface layer cancomprise a set of conductive portions or inserts that each contact aunique key 214. Thus, applying a capacitive load to the conductiveportion of the flexible surface layer can enable that load to passthrough the flexible surface layer to the key 214 within.

In the configuration shown in FIG. 2, the computing device 202 isarranged with the touch screen 210 where the user can view the touchscreen 210 while also being able to view and interact with the keyboard212 in a normal laptop-computer-like orientation. In embodiments wherethe input device 204 is integrated with a stand or support for thecomputing device 202, the input device 204 can be arranged to beconfigurable in the relative position shown in FIG. 2 while thecomputing device 202 is also arranged in the relative position shown inFIG. 2.

FIG. 4 shows that the input device 204 can have a set of conductivetraces 226 positioned in the input section 216 and contact section 218.In FIG. 4, the keys 214 and top surface 222 are removed from a breakawayportion 207 of the input device 204 to show the location of conductivepads 228 that lie beneath the keys 214. The non-breakaway portion 205shows the keys 214 in their normal configuration. Each of the keys 214in the keyboard 212 can have its own unique conductive pad 228 in theinput section 216 that is linked to its own unique conductive trace 230and a unique conductive pad 232 in the contact section 218. Thus, eachset of these elements 228, 230, 232 can be a conductive portion of theinput device 204 referred to as a conductive trace (e.g., 112) or aconductive lead.

The conductive pads 228 in the input section 216 can be arranged in akeyboard layout. Alternatively, the conductive pads 228 can be replacedby conductive leads that merely connect to the switches of each of thekeys 214. Thus, although the conductive pads 228 are shown in FIG. 4 forreference, it will be understood that the pads 228 are merelyrepresentative of conductive elements of some kind that are connected toswitches in the keyboard 212 and that are connected to the conductivetraces 230. Further, the scale and shape of the pads 228 can be modified(e.g., enlarged or reduced in size) to fit the needs of a particularconfiguration. In some embodiments, the conductive pads 228 are omitted,and a direct connection to an electrical lead on a switch or similarstructure is made to the conductive traces 230.

The conductive pads 232 in the contact section 218 can be roughlyarranged in a straight row, a set of rows, a straight column, a set ofcolumns, a staggered set of rows (as shown in FIG. 4), a keyboardlayout, another comparable pattern, or combinations thereof. Theconductive pads 232 can be arranged in rows corresponding to a widthbetween scan rows of a touch-sensitive interface (e.g., electrical pathsthrough touch screen 210). The size of the conductive pads 232 can beconfigured so that a typical capacitive load (e.g., a capacitive load ofa finger) applied through the conductive pads 232 has a sufficientmagnitude (when emitted at the conductive pads 232) to be detected bythe touch-sensitive interface of the computing device 202. In someembodiments, the size of the conductive pads 232 is therefore configuredto simulate the touch of a human finger against the computing devicewhen a capacitive load of a human finger is applied to its correspondingconductive trace 230. The material used in the conductive pads 232 canalso affect their size and shape. The conductive pads 232 can bereferred to as electrodes or conductors in the contact section 218.

The embodiment of FIG. 4 shows one layout of the conductive pads 232wherein they are configured to overlay the touch screen 210 in region234. This region 234 can be referred to as a border region (or alengthwise border region) of the touch screen 210 since it is locatedalong a border of the touch screen 210 (and is oriented lengthwiserelative to the touch screen 210). The width of the border region 234can be equal to a width W of the portion of the contact section 218 thatincludes all of the conductive pads 232. Thus, when the contact section218 is overlaid on the border region 234, all of the conductive pads 232can be located within the border region 234, thereby enabling all of thekeys 214 to be registered at unique locations on the touch screen 210through the conductive pads 232.

In some embodiments, the conductive pads 232 can overlay a bezel region236 on the computing device 202. The bezel region 236 is on the frontsurface 208 and is not part of the display screen but is insteadadjacent thereto. Thus, the conductive pads 232 do not cover the touchscreen 210, thereby leaving additional uncovered screen space (i.e., theborder region 234 is not covered). The computing device 202 can includea touch-sensitive interface (e.g., 108 or 208) that is positioned within(or extends into) the bezel region 236 in this case so that theconductive pads 232 can each be sensed by the interface.

In other embodiments, the conductive pads 232 can be overlaid againstthe border region 234 and the bezel region 236 simultaneously. This canbe beneficial when a large number of (or large size of) conductive pads232 is implemented in the contact section 218 to avoid taking upadditional screen space. In yet other embodiments, the contact section218 can extend around the touch screen 210 to one or more other portionsof the front surface 208, such as to a top border region 238 or topbezel region 240 at a top end 242 of the computing device 202, to abottom border region 244 or bottom bezel region 246 at a bottom end 248of the computing device 202, to other regions on the front surface 208or rear surface 250 (see FIGS. 3 and 6) of the computing device 202, orcombinations thereof. Accordingly, the contact section 218 andconductive pads 232 can be arranged to contact any external surface ofthe computing device 202.

In some embodiments, conductive pads 232 can be positioned on the sidesor rear surface 250 of the computing device 202. See, e.g., FIGS. 6-8and their related descriptions herein.

FIG. 5 is a diagrammatic side section view through the input device 204,as indicated by section line 5-5 in FIG. 4. To facilitate convenientreference, sizes and shapes of components are not shown to scale, andsome components are not shown. The input section 216 and contact section218 can be positioned at opposite ends of the input device 204 and caneach comprise a set of layers 251, 252, 254 in a substrate or housing256.

The housing 256 can comprise a rigid material (e.g., made of a compositesuch as FR-4 or a comparable material) or a flexible material (e.g.,made of thermoplastic polyurethane (TPU), silicone, reinforced silicone,thin sheet metal, a bendable polymer, or a comparable material) for thelayers 251, 252, 254. The housing 256 can include the embeddedconductive traces 226 positioned through the layers 251, 252, 254. Forexample, a conductive switch pad 256 can be positioned in the top layer251, a conductive electrode pad 258 can be positioned in the bottomlayer 254, and a conductive trace 260 can electrically connect theswitch pad 256 to the electrode pad 258 through the middle layer 252.The switch pad 256 can be one of the conductive pads 228, the electrodepad 258 can be one of the conductive pads 232, and the conductive trace260 can be one of the conductive traces 230 of FIG. 4. See FIG. 4. Insome embodiments, the layers 251, 252, 254 can be covered by anadditional coating or layer through which a capacitive load coming fromthe conductive elements can be detected.

In some embodiments, only two layers 251, 254 are provided, and theconductive trace 260 can be embedded between them. In anotherembodiment, all of the layers 251, 252, 254 may be formed as a singlelayer with the pads 256, 258 and conductive trace 260 embedded therein.

A switch 262 can be positioned at the switch pad 256. The switch 262 cancomprise a corresponding keycap 264. The keycap 264 can be one of thekeycaps 214 of FIGS. 2-3. The switch 262 can comprise a conductiveportion 266, and the keycap 264 can comprise a conductive material incontact with the conductive portion 266. Accordingly, when a capacitiveload is applied to the keycap 264, the conductive path through thekeycap 264 and the conductive portion 266 can transfer the capacitiveload to the inside of the switch 262. The switch 262 can be collapsibleto a position (not shown) where the conductive portion 266 contacts theswitch pad 256. This can occur when a user presses down on the keycap264 in the direction of arrow 268. Thus, the capacitive load can betransferred from the keycap 264 to the electrode pad 258 via theconductive portion 266, switch pad 256, and conductive trace 260.Accordingly, if the electrode pad 258 is within an operative, detectabledistance from a touch-sensitive interface (e.g., 108), the capacitiveload applied at the keycap 264 can be registered or detected by theinterface.

The switch 262 can be a collapsible dome, an inverted collapsible dome,a mechanical switch (e.g., an elastically movable contactor-basedswitch), or a related switch used in keyboards. The switch 262 canprovide tactility, feedback, resistance, and sound to the operation ofthe keyboard 212. The switch 262 can be supported by a housing (e.g., arigid housing, plate, flexible membrane, and related elements), astabilizer (e.g., a scissor mechanism or butterfly mechanism), and othercomponents used in keyboards. These features can help resist the ingressof debris or fluids into or around the switch 262, can help preventaccidental dislodgement of the keycap 264 from the switch 262, canimprove aesthetics, can help ensure parallel motion of the keycap 264relative to the top surface 222 (i.e., support the keycap 264 so thatits top surface remains parallel to the top surface 222 while inmotion), and can perform other functions to improve the look, feel, andfunction of the keyboard 212. If a coating or layer covers the keycap264 or is positioned between the keycap 264 and the switch 262, thecoating or layer can include a conductive material or a conductiveportion to preserve the conductive path from the user's hand to theelectrode pad 258. The coating or layer covering the keycap 264 can alsobe used as a shield to insulate conductive material in key switches(e.g., conductive portion 266) within the input device 204 and tothereby limit or prevent registration of accidental key presses causedby incidental or inadvertent contact between a finger and the keycap264. Thus, the conductive path can extend from a ground to an electrodepad (e.g., 458) in the input device. See also FIGS. 7 and 8 and theirrelated descriptions below.

If the switch 262 is a dome switch, it can comprise a conductive metaldome, a flexible dome having a conductive insert, a conductively-dopedrubber dome, a conductively-doped silicone dome, or anotherconductively-doped flexible material. Thus, the switch 262 can provide aconductive path in various ways. In some embodiments, the conductivepath from the keycap 264 does not extend through the switch 262, butmovement of the switch 262 enables the conductive path to be connectedbetween the keycap 264 and the switch pad 256. For example, the switchcan support the movement of the keycap 264 between a first positiondisconnected from the switch pad 256 and a second position where thekeycap 264 (or an extension thereof) is in conductive contact with theswitch pad 256.

In yet other embodiments, the switch 262, keycap 264, and supports andcoverings for the switch 262 and keycap 264 can be omitted. In thiscase, the user can directly contact the switch pad 256 with their fingeror another capacitive load. Alternatively, the keycap 264 can beomitted, and the user can directly touch the switch 262. Still further,the switch 262 can be omitted and the keycap 264 can be in constantcontact with the switch pad 256. Thus, the switch 262 and keycap 264 arenot required for operation of the input device 204. In some embodiments,a first set of conductive pads 228 can have corresponding switches 262and keycaps 264, another set of pads 228 can have only switches 262 oronly keycaps 264, and another set of pads 228 can have neither switches262 nor keycaps 264.

FIGS. 3 and 6-8 illustrate additional embodiments of the input device304 wherein the input device 304 is configured to contact a back or rearsurface 350 of the computing device 302. As shown in FIGS. 3 and 6, theinput device 304 can comprise an input section 316 and a contact section318 with a hinge 320 that is positionable underneath the computingdevice 302 when the computing device 302 is in an upright orientationrelative to a horizontal direction. The contact section 318 can have afront-facing surface 321 configured to contact a rear-facing surface 350of the computing device 302. The rear-facing surface 350 can thereforecomprise a touch-sensitive interface 309 corresponding to thefront-facing surface 321 in size and position. Accordingly, the inputdevice 304 can transfer capacitive load from the keys 314 to thetouch-sensitive interface 309 via conductive leads similar to the traces226. Conductive pads similar to pads 232 can be positioned on thefront-facing surface 321 to enable this interaction. In someembodiments, the rear surface 350 can be configured with a materialthrough which a capacitive load can be locally transferred, such as, forexample, a glass or polymer material.

The input device 304 can be foldable or bendable at the hinge 320.Accordingly, the input section 316 can be folded to cover the frontsurface of the computing device 302 while the contact section 318 ispositioned against the rear surface 350. In that configuration, the keys314 can face toward or contact the front surface of the computing device302, and the computing device 302 itself can help protect and cover thekeys 314.

The touch-sensitive interface 309 can be part of a touch-sensitiveinterface that is used to detect touch input on a display screen on thefront surface 308 of the computing device 302. The touch-sensitiveinterface for the display screen can extend through the interior of thecomputing device 302 from the front surface 308 to the region for thetouch-sensitive interface 309 shown in FIG. 6. For example, theinterface for the touch screen can wrap around or fold within the insideof a housing of the computing device 302 to provide touch-sensitivity atthe rear surface 350. Alternatively, the touch-sensitive interface 309can be a separate component from any touch interface of the frontsurface 308.

In some embodiments, the touch-sensitive interface 309 can betouch-sensitive, wherein contact with a finger against thetouch-sensitive interface 309 can be detected by the computing device302. In some of these configurations, the computing device 302 can beconfigured with software that ignores or disables touch interaction withthe rear touch-sensitive interface 309 unless the presence of a contactsection 318 is also detected (e.g., by a Hall-effect sensor detectingmagnets in the contact section 318 at the rear surface 350).

Referring again to FIGS. 3 and 6, the contact section 318 can beconfigured to cover or extend along an edge or bezel portion of the rearsurface 350 of the computing device 302. In some embodiments, a contactsection 370 can be enlarged relative to contact section 318, wherein thecontact section 370 extends across a majority or entirety of the rearsurface 350 of the computing device 302. In such an embodiment, thecontact section 370 can have conductive pads distributed across itsentire front surface 321 to interact with a large touch-sensitiveinterface 311 through the rear surface 350. In some configurations, thecontact section 370 can still have conductive pads localized enough tointeract with a smaller touch-sensitive interface (e.g., 309) that issubstantially smaller in area than the area of the front surface 321 ofthe contact section that is in contact with the rear surface 350 of thecomputing device.

FIG. 7 illustrates an example embodiment of an input device 404configured with a large contact section 418. This input device 404 canhave similar features in its input section 416 as the input section 216shown in FIG. 4 with its pads 428 and traces 430. FIG. 7 is also shownwith a breakaway section 407, wherein keycaps and other upper portionsof the input device 404 are removed to reveal inner conductive elementsof the input device 404, and a non-breakaway section 405 showing anormal top view of the input device 404. In this view, the breakawaysection 407 does not extend to the large conductive pad 440. Theconductive pads 432 may differ from conductive pads 232 by being on atop surface/front-facing surface 421 of the contact section 418. Beingpositioned on the front-facing surface 421 of the contact section 418can permit the pads 432 to contact a rear surface of an electronicdevice (e.g., 350).

The contact section 418 can also comprise a large conductive pad 440that is larger than, and insulated from, the other conductive pads 432.The large conductive pad 440 can be referred to herein as a virtualground pad, a low impedance to ground pad, or a capacitive ground pad.The increased size of the large conductive pad 440 can make it have alow impedance to ground (relative to the smaller conductive pads 432)and thereby make it act as a virtual ground when instantaneouslyelectrically connected to the smaller conductive pads 432. It can alsobe connected to, or replaced by, an external ground source (e.g., a wireto ground (e.g., via a power cable for the computing device 302) or agrounded conductive surface of the computing device 302). The largeconductive pad 440 can be capacitively coupled to the system ground ofthe electronic device chassis through any insulating material positionedbetween the pad 440 and the ground within the computing device 302. Thelarge conductive pad 440 can therefore be referred to as a capacitiveload source contained within the input device 304. The large conductivepad 440 can be designed to have a larger size relative to the smallerconductive pads 432 wherein if both types of pads 432, 440 are incontact with a dielectric surface (e.g., an anodized aluminum body onthe computing device or the like), the larger pad 440 will be sized toinduce a sufficient capacitive load to be detectable by thetouch-sensitive interface of the computing device when that load istransferred to one of the smaller pads 432. In this manner, electricallyconnecting the large conductive pad 440 to one of the other conductivepads 432 can give the same electrical effect as a finger preciselytouching one of the other conductive pads 432. In some embodiments,there is no direct DC connection to the system ground, the potential atthe other conductive pads 432 is electrically equivalent to ground dueto the high capacitance made by the large conductive pad 440 and thechassis of the computing device.

The larger pad 440 can be selectively electrically connected to each ofthe conductive pads 428 in the input section 416 or to each of theconductive pads 432 in the contact section 418. The connection can beenabled or disabled by switches (e.g., switch 462 in FIG. 8) in theinput device 404.

FIG. 8 is a diagrammatic side section view of an embodiment of inputdevice 404, as suggested by section line 8-8 in FIG. 7. To facilitateconvenient reference, sizes and shapes of components are not shown toscale, and some components (e.g., a possible mechanical stabilizer forkeycap 464) are not shown. The input section 416 and contact section 418can be positioned at opposite ends of the input device 404 and can eachcomprise a set of layers 450, 452, 454 in a substrate or housing 456.The housing 456 can have the properties of housing 256.

The housing 456 can include embedded conductive traces positioned in thelayers 450, 452, 454. For example, a conductive switch pad 456 and aconductive electrode pad 458 can be positioned in the top layer 450, anda conductive trace 460 can electrically connect the switch pad 456 tothe electrode pad 458 through the middle layer 452. The switch pad 456can be one of the conductive pads 428, the electrode pad 458 can be oneof the conductive pads 432, and the conductive trace 460 can be one ofthe conductive traces 430 of FIG. 7.

In this embodiment, the external surfaces of the keycap 464 can benon-conductive. Thus, contact with a finger against the keycap 464 wouldnot transfer a detectable capacitive load through the input device 404to the electrode pad 458. Instead, the switch 462 can comprise aconductive portion 466 (or can be formed with a conductive material, asexplained elsewhere herein), and the conductive portion 466 can move asthe switch 462 collapses to complete a conductive path between a secondswitch pad 468 and the first switch pad 456. The second switch pad 468can be connected via a conductive trace 470 to a capacitive load source472 (e.g., large pad conductive 440 or a connection to a ground sourceor a virtual or relative ground source) and can therefore transfer acapacitive load to the electrode pad 458 without passing through thekeycap 464 or without being sourced from a user's appendage or otherinstrument applied to the keycap 464. The first and second switch pads456, 468 can be separated by an air gap 467 or insulator that preventsconduction between the first and second switch pads 456, 468 when theswitch 262 is not closed. Other types of switches and configurations ofconductors and pads can be used as well. For example, the dome of switch462 can be inverted such that an upward-facing surface of the dome isconcave instead of convex.

While reference is made herein to parts and features being “horizontal”and “vertical,” it will be understood by those having ordinary skill inthe art that these orientations are provided for convenience indescribing features of the embodiments disclosed herein and should notbe construed as limiting these embodiments to operating only in theorientations shown or described. Thus, although portions of the deviceare described with reference to vertical or horizontal directions, thedevices in the present disclosure can be oriented at any angle.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice the describedembodiments. Thus, the foregoing descriptions of the specificembodiments described herein are presented for purposes of illustrationand description. They are not target to be exhaustive or to limit theembodiments to the precise forms disclosed. It will be apparent to oneof ordinary skill in the art that many modifications and variations arepossible in view of the above teachings.

What is claimed is:
 1. A computing device and keyboard assembly,comprising: a computing device having a housing containing acapacitance-sensing interface and a display screen; a keyboard coupledto the computing device and having: an input section; a coupling sectionpositioned at a detectable distance from the capacitance-sensinginterface of the computing device; and a set of conductors extendingthrough the keyboard, each conductor of the set of conductorscomprising: a first end portion located in the coupling section; and asecond end portion located in the input section; wherein thecapacitance-sensing interface of the computing device is configured todetect an application of a capacitive load to the second end portion viathe first end portion.
 2. The assembly of claim 1, further comprising anintermediate layer positioned between the capacitance-sensing interfaceand the coupling section.
 3. The assembly of claim 1, wherein thecapacitance-sensing interface and the coupling section are positionedout of contact with each other.
 4. The assembly of claim 1, wherein thecapacitance-sensing interface is spaced away from the display screen. 5.The assembly of claim 1, wherein the capacitance-sensing interface isoperable at the display screen.
 6. The assembly of claim 1, wherein thecoupling section and the input section are joined by a hinge.
 7. Theassembly of claim 1, wherein the keyboard is attachable to the computingdevice in an input position wherein the input section and the displayscreen are visible and in a stored position wherein the display screenis covered.
 8. The assembly of claim 1, wherein the first end portionsof the set of conductors are distributed across an edge portion of thecomputing device.
 9. The assembly of claim 1, wherein the computingdevice is configured to detect a presence of the coupling section of thekeyboard at the capacitance-sensing interface.
 10. A keyboard,comprising: a housing having a first section and a second section, thefirst section having an external surface configured to face anelectronic device, the second section being configured to extend awayfrom the electronic device; and a set of conductive leads positioned inthe housing, each conductive lead of the set of conductive leadscomprising: a first conductive portion positioned at the externalsurface of the first section and configured to be detectable by acapacitance-sensing interface of the electronic device; and a secondconductive portion positioned in the second section; wherein each of thesecond conductive portions of the set of conductive leads is configuredto passively transfer capacitive loads from an external object torespective first conductive portions.
 11. The keyboard of claim 10,further comprising a set of switches, wherein each switch of the set ofswitches is positioned adjacent to a separate second conductive portionof the set of conductive leads.
 12. The keyboard of claim 11, furthercomprising a set of keycaps respectively configured to actuate the setof switches upon application of an input force to the set of keycaps.13. The keyboard of claim 11, wherein each switch of the set of switchescomprises a conductive material capable of transferring capacitive loadto a respective second conductive portion of the set of conductiveleads.
 14. The keyboard of claim 10, further comprising a coating orexternal layer covering at least one of the first conductive portions.15. The keyboard of claim 10, wherein the first section is angledrelative to the second section.
 16. A capacitive touch input device,comprising: a housing having an input portion and a pad portion; a setof conductive traces extending from the input portion of the housing tothe pad portion of the housing and defining a set of passive conductivepaths though the housing; wherein a capacitive load applied at the inputportion of the housing is detectable at the pad portion of the housingvia passive transfer through at least one of the conductive traces ofthe set of conductive traces.
 17. The capacitive touch input device ofclaim 16, further comprising a set of keys at the input portion, each ofthe set of keys respectively corresponding to each of the conductivetraces.
 18. The capacitive touch input device of claim 16, furthercomprising a coating or external layer covering the pad portion of thehousing.
 19. The capacitive touch input device of claim 16, wherein thepad portion comprises a set of conductive pads, each respectively beingin electrical communication with the set of conductive traces.
 20. Thecapacitive touch input device of claim 16, further comprising aconnection to an electrical ground, wherein the capacitive load isapplicable to a conductive trace of the set of conductive traces byelectrically connecting the conductive trace to the electrical ground.